STARTING FROM THE GROUND UP!
Healthy soil is the key to any successful garden. It is the foundation on which a healthy garden is built. Over the past few years, we have relied heavily upon synthetic fertilizers as a way of trying to produce larger, healthier plants with the hopes of them producing a larger quantity of produce. But the one thing that we have forgotten is that the plants are not the only things that need to be fed. The basic principle that gardeners should live by is that if you feed the soil, the soil will feed your plants.
We tend to think that the plants are the only living component in the garden. What we forget is that the soil is also alive with many different organisms. The top 12” of your soil, where most of your plant’s roots feed and grow, is teeming with bacteria, fungi and countless other microscopic creatures. Most of these are beneficial and some are even essential to keeping your plants healthy. Therefore, the challenge for gardeners is to balance your soil so that it provides all the conditions plants need in order to thrive. You may wonder why the soil in your garden would be out of balance. There are several reasons:
- The surface soil on many new properties has been scraped away before the house was built and never replaced.
- Equipment and repeated walking on the soil compacts it and harms it’s structure.
- Your soil’s natural characteristics may not be favourable for gardening. For example: you may have very sandy soil that does not hold sufficient water or nutrients to support your plants. Or your soil may be too acidic for the kinds of plants that you would like to grow.
- Your soil may be depleted of nutrients due to over use.
- If you use a lot of chemical fertilizers, the soil’s micro-organisms that are essential for plant growth, may have died off.
Therefore, the step first step for improving your soil is to learn about its characteristics.
ALL THE DIRT ON SOIL
Soil is much more than just dirt. Soil is an intricate mix of fine rock particles, organic matter, water, air, micro-organisms and other animals. A healthy soil is full of living things: roots, animals, insects, bacteria, fungi and other organisms. Managing your soils to keep this living system thriving can make the difference between gardening success and failure. So what is your soil made up of?
Soil is nearly half minerals and half water and air. Organic matter makes up only a small percentage of the soil. But for successful gardeners, maintaining organic matter content is critical. Soil life, including mammals, reptiles, insects and micro-organisms, transforms organic matter into nutrients that can be taken up by your plants.
When we look at a handful of soil, we often overlook the fact that we are actually looking at 3 different types of particles – sand, silt and clay. And what you probably don’t realize is that these 3 particles are different in size from one another. Even though the size difference between the particles seems insignificant, it is actually of great importance. The relative proportion of these tiny particles influences soil water retention, air drainage and fertility. The tiny spaces between the particles are the holding areas for water and for the dissolved nutrients that can be absorbed by roots.
Sand particles measure anywhere from 0.05 to 2.0 millimetres in diameter. They are the largest of the 3 particles. Because the particles are larger, they do not fit together as tightly as silt and clay particles do. Therefore, there are more and larger air gaps in between the particles. Sandy soils often do not hold enough water to support the growth of many kinds of plants. Sandy soils tend to be less fertile because they have less surface area where nutrients can be held. If you were to squeeze together a handful of sand. It would not maintain any shape.
Silt particles range in size from 0.002ml to 0.05ml in diameter. The particles feel smooth and rather silky. Individual silt grain cannot be seen with the naked eye and are so fine that they cannot be individually felt with your fingers. It retains water well but releases it more slowly than sand.
Clay particles are the smallest and measure less than 0.002ml in diameter. Clay forms extremely hard lumps when it is dry and is extremely sticky when it is wet. The clay particles tend to stick together when wet. This means that it retains water well, but also means that water does not drain through it well. Clay tends to form surface crusts that water cannot penetrate. Because the particles are so small there is very little air spaces in between particles. This also makes it difficult for roots to make their way through the soil. When you pick up some moist clay in your hands and squeeze it remains in a tight ball shape.
What’s Next: Where to Start: Planting Instructions
So what is the best type of soil?
The best soil is a balanced mixture of sand, silt and clay. This type of soil is called loam. Loam is relatively soft and crumbly and slightly gritty to the touch. It will retain and release water at a moderate rate.
How to check your own soil – Jar of water test (approximate method)
Place one or two cups of soil in a clear glass jar that holds about 1 litre and add water almost to the brim. Shake the mixture vigorously for a few minutes then let it stand for at least 24 hours, because the clay may take several days to settle (it will settle more quickly if you add 2 tsp table salt).
The mixture will gradually form layers, with sand on the bottom of the jar, silt in the middle and clay on top. Organic matter will float to the surface. You can calculate the percentage of each element according to the depth of each layer.
% sand: (depth of the sand layer X 100) ÷ total depth of the soil in the jar % silt: (depth of the silt layer X 100) ÷ total depth of the soil in the jar % clay: (depth of the clay layer X 100) ÷ total depth of the soil in the jar
The following jar contains about 73% sand, 20% silt and 7% clay. The soil has a sandy texture. % sand = (5.5 cm X 100) ÷ 7.5 cm = 73% % silt = (1.5 cm X 100) ÷ 7.5 cm = 20% % clay = (0.5 cm X 100) ÷ 7.5 cm = 7%
Then you can use the following table to classify your soil:
|Soil texture||% sand||% silt||% clay|
|Sandy soil||70 or more||0 to 30||0 to 15|
|Silty soil||0 to 20||80 or more||0 to 15|
|Clay soil||0 to 45||0 to 40||25 or more|
|Loam||40 to 60||30 to 50||15 to 25|